This touches on the following:

- build configurations
- naming of symbols, shared/static libraries and other build outputs
  like pkg-config and CMake files
- (in more detail) guidance on ILP64 builds

It tries to explain that, while this is only guidance and there may be
reasons to deviate from that, for some build options there are best
practices, and for some others there are choices to make.

It also links to a number of well-maintained build recipes in order
to help packagers of other distros make choices.

Closes gh-3798

[skip ci]

* Fix actual arguments (Reference-LAPACK PR 885)

Ensure that early calls to blas_set_num_threads will not overwrite unrelated memory

Override the C910V DSDOT with generic code to get rid of the qemu precision error in CI

Fix runtime detection in ARMV8 DYNAMIC_ARCH to check SVE capability

Cirrus CI: Add Apple M1 build using gcc,gmake and OpenMP

Support Alder Lake N (family 6 exmodel 11 model 14) as Haswell

Fix armv8 detection in system_check.cmake

Fix riscv64 detection in system_check.cmake

* Fix workspace query corner cases to always return at least 1

* Fix prototypes for ?GEDMD/?GEDMDQ and their LAPACKE interfaces

Restore zero-initialization of variables in generic ztrsm_utcopy

* Add AppleClang crossbuild to MacOS/arm64 DYNAMIC_ARCH

* add casts to disambiguate svwhilelt for clang

* Fix gcc version checks erroneously excluding clang

* Avoid some mtune names not supported by (Apple)Clang

The cmake scripts incorrectly treated armv8 as 32-bit arm, causing
compilation issues. This just adds 'armv8' to the arm64 condition check.

Add converted C versions of C/ZRSCL to fix build errors introduced by PR4126

Fix info code returned for invalid ldb by IMATCOPY

Fix computation of UPLO in LAPACKE_?larfb (Reference-LAPACK PR 878)

Fix segfault in ?GELSS when NRHS is zero (Reference-LAPACK PR 876)

Add C/ZRSCL for reciprocal scaling of a complex vector (Reference-LAPACK PR 839)

Correct order of eigenvals/vecs for 2x2 matrices in ?STEMR (Reference-LAPACK PR 867)

Fix CMAKE builds of SVE-capable targets in arm64 DYNAMIC_ARCH

Add status badges for OSUOSL's POWERCI and IBMZ-CI services to README.MD

LoongArch64: Add WhereAmI()

* Fix Apple crossbuilds after Cirrus updated the image; add a crossbuild to Android/ARMV7